If I’m reading you right about where you want to go, I agree a 28’ is too big. Especially since sizes seem understated, maybe they’re using box length and you have to add another 3’ or so to get the real length. You have the advantage over me because you know where you went before while I have to speculate. But my feeling after many decades of camping out west, off the beaten path, is that to get well back in somewhere it’s best to stay under 20’. 24’ is about the max I’d go if I wanted more room, but that would limit me to not getting too far off a decent road. But the bulk of my camping is on forest service roads in the national forests and they’re not graded or “improved”.
So it really depends just how far off the beaten path you want to get. My suggestion would be stay below 25’, but that’s not much of an improvement over what you already have. I think you’ll have find something big enough that you’re happy with the space and accept whatever limitation that imposes on you as far as where you can go. I have a 16’ because I can get it about anywhere I want to go and that’s my number 1 priority. But even I’ll admit I wouldn’t want to live in it in an RV park for any extended period of time. Good luck with your decision.